1. The Field of the Invention
The present invention pertains in general to computer software operating systems, and more particular to a river for a class of devices which generate or receive streaming data.
2. The Relevant Technology
A rapidly growing area of interest in the field of computer technology is that of “multimedia”. This term generally refers to the concurrent use of video and audio in a computer system for a wide range of applications including business and entertainment.
The primary applications which have led to the tremendous success of personal computers have been based on the power of these computers to process numbers in complex ways such as through spreadsheets, graphics, word processing and data bases. However, in such applications, the application program works with a discrete data file and typically works with only a small part of such a data file at any one time. Multimedia applications add a major new aspect to the processing of data by personal computer. This is the requirement to manage and process a continuous stream of data as opposed to discrete data files which are typically processed by an application program. The stream of data associated with a multimedia application is generally far too large to be loaded in memory, and in many cases the data is continuous with no predetermined end of the data. A further feature of multimedia streaming data is that it is sequential in nature and frequently is time dependent, that is, it must not only be processed in a specific sequential order, it must also be processed to produce precisely times sequential events.
An example of multimedia streaming data is the output which is produced by a DVD (Digital Versatile Disk) apparatus. The contemporary DVD apparatus produces data using the MPEG-2 video and audio format. This output actually comprises three separate data streams which are video, audio and subpicture. Each of these streams requires separate processing, but the results of the processing must be time synchronized and generated at a predetermined absolute rate to obtain the desired results. Video and audio signals must be properly synchronized and timed to generate a viable multimedia presentation.
A standardized computer platform, including hardware and software, must be able to work a large number of independently produced multimedia adapters, such as DVD players, video cameras, audio sources and ROM discs. Each of these products requires a separate, complex driver which functions to interface application programs through the computer operating system to the specific hardware in order to process the multimedia streaming data to produce continuous outputs. However, to accommodate the massive amounts of data and the extensive, complex processing of this data required for a successful multimedia application, the driver must be highly efficient, well designed and capable of performing a wide range of functions within the operating system and functions required by the application program. With the growing complexity of operating systems and the greater demands of application programs, it is very difficult for each independent producer of a hardware device, particularly for multimedia, to produce an efficient, current and effective driver for that product. Thus, there exists a need to reduce the burden of producing drivers for multimedia products.
In other areas of computer system operation, such as for pointing devices, for example, a mouse, it has been proposed to have a hardware independent driver associated with the operating system and have a hardware dependent driver provided by the hardware manufacturer for each particular device. See U.S. Pat. No. 5,465,364 entitled “Method and System for Providing Device Driver Support Which is Independent of Changeable Characteristics of Devices and Operating Systems.” Pointing Devices, however, do not have the same problems that are encountered with multimedia applications. The data rate for pointing devices is extremely low, the data processing is not particularly complex and the pointing device is extremely low, the data processing is not particularly complex and the pointing device is generally a support aspect of an application program, in contrast to being an aspect that is a principle part of a multimedia application.
In view of the substantial problems encountered in the use of multimedia applications on personal computes, and the insatiable consumer demand for greater bandwidth and data processing sophistication, there is a need for a multimedia driver configuration which can efficiently handle the volume and complexity of streaming data while at the same time minimizing the burden and difficulty of driver design for the independent developers and manufacturers of multimedia products.